antral lavage
The method is called irrigation and the water is passed through conduits or ditches called irrigation channels from the water source (well, river, stream) to where the crops need the water.
They would get it from the local stream. They might have to use irrigation or carry the water to get it to them.
A stream or river called that flows into a larger stream or river is called a tributary.
A small stream is called a creek.
The side of a stream is usually called its bank.
It is occasionally called a sinking stream or a disappearing stream, but geographers and geologists normally call it a stream, just like another stream.
it's a type of irrigation in which construction of small dams or bandharas are made which are 1.25 to 4.5 high across the river or stream to raise the water level to feed the nearby canals.
Tributary is the answer you are looking for, I believe.
a waterway is a large stream
a tributary
a stream
Kenneth C. Mitchell has written: 'Characterizing and modeling water level fluctuations in irrigation canals' -- subject(s): Irrigation canals and flumes, Stream measurements, Measurement